/** @return Whether the name is used in a way that might be a candidate for inlining. */
static boolean isCandidateUsage(Node name) {
Node parent = name.getParent();
Preconditions.checkState(name.isName());
if (parent.isVar() || parent.isFunction()) {
// This is a declaration. Duplicate declarations are handle during
// function candidate gathering.
return true;
}
if (parent.isCall() && parent.getFirstChild() == name) {
// This is a normal reference to the function.
return true;
}
// Check for a ".call" to the named function:
// CALL
// GETPROP/GETELEM
// NAME
// STRING == "call"
// This-Value
// Function-parameter-1
// ...
if (NodeUtil.isGet(parent)
&& name == parent.getFirstChild()
&& name.getNext().isString()
&& name.getNext().getString().equals("call")) {
Node gramps = name.getAncestor(2);
if (gramps.isCall() && gramps.getFirstChild() == parent) {
// Yep, a ".call".
return true;
}
}
return false;
}
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getType()) {
// Function calls
case Token.CALL:
Node child = n.getFirstChild();
String name = null;
// NOTE: The normalization pass insures that local names do not
// collide with global names.
if (child.isName()) {
name = child.getString();
} else if (child.isFunction()) {
name = anonFunctionMap.get(child);
} else if (NodeUtil.isFunctionObjectCall(n)) {
Preconditions.checkState(NodeUtil.isGet(child));
Node fnIdentifingNode = child.getFirstChild();
if (fnIdentifingNode.isName()) {
name = fnIdentifingNode.getString();
} else if (fnIdentifingNode.isFunction()) {
name = anonFunctionMap.get(fnIdentifingNode);
}
}
if (name != null) {
FunctionState fs = functionMap.get(name);
// Only visit call-sites for functions that can be inlined.
if (fs != null) {
callback.visitCallSite(t, n, fs);
}
}
break;
}
}
/** If this is an assign to a variable or its property, return it. Otherwise, return null. */
static Assign maybeCreateAssign(Node assignNode) {
Preconditions.checkState(NodeUtil.isAssignmentOp(assignNode));
// Skip one level of GETPROPs or GETELEMs.
//
// Don't skip more than one level, because then we get into
// situations where assigns to properties of properties will always
// trigger side-effects, and the variable they're on cannot be removed.
boolean isPropAssign = false;
Node current = assignNode.getFirstChild();
if (NodeUtil.isGet(current)) {
current = current.getFirstChild();
isPropAssign = true;
if (current.getType() == Token.GETPROP
&& current.getLastChild().getString().equals("prototype")) {
// Prototype properties sets should be considered like normal
// property sets.
current = current.getFirstChild();
}
}
if (current.getType() == Token.NAME) {
return new Assign(assignNode, current, isPropAssign);
}
return null;
}
/**
* Check that Node n is a call to one of the jQuery.extend methods that we can expand. Valid calls
* are single argument calls where the first argument is an object literal or two argument calls
* where the first argument is a name and the second argument is an object literal.
*/
public static boolean isJqueryExtendCall(Node n, String qname, AbstractCompiler compiler) {
if (JQUERY_EXTEND_NAMES.contains(qname)) {
Node firstArgument = n.getNext();
if (firstArgument == null) {
return false;
}
Node secondArgument = firstArgument.getNext();
if ((firstArgument.isObjectLit() && secondArgument == null)
|| (firstArgument.isName()
|| NodeUtil.isGet(firstArgument)
&& !NodeUtil.mayHaveSideEffects(firstArgument, compiler)
&& secondArgument != null
&& secondArgument.isObjectLit()
&& secondArgument.getNext() == null)) {
return true;
}
}
return false;
}
/**
* There are two types of calls we are interested in calls without explicit "this" values (what
* we are call "free" calls) and direct call to eval.
*/
private static void annotateCalls(Node n) {
Preconditions.checkState(n.isCall());
// Keep track of of the "this" context of a call. A call without an
// explicit "this" is a free call.
Node first = n.getFirstChild();
// ignore cast nodes.
while (first.isCast()) {
first = first.getFirstChild();
}
if (!NodeUtil.isGet(first)) {
n.putBooleanProp(Node.FREE_CALL, true);
}
// Keep track of the context in which eval is called. It is important
// to distinguish between "(0, eval)()" and "eval()".
if (first.isName() && "eval".equals(first.getString())) {
first.putBooleanProp(Node.DIRECT_EVAL, true);
}
}
/**
* @param n The node in question.
* @param cfgNode The node to add
* @param conditional true if the definition is not always executed.
*/
private void computeMustDef(Node n, Node cfgNode, MustDef output, boolean conditional) {
switch (n.getType()) {
case Token.BLOCK:
case Token.FUNCTION:
return;
case Token.WHILE:
case Token.DO:
case Token.IF:
computeMustDef(NodeUtil.getConditionExpression(n), cfgNode, output, conditional);
return;
case Token.FOR:
if (!NodeUtil.isForIn(n)) {
computeMustDef(NodeUtil.getConditionExpression(n), cfgNode, output, conditional);
} else {
// for(x in y) {...}
Node lhs = n.getFirstChild();
Node rhs = lhs.getNext();
if (NodeUtil.isVar(lhs)) {
lhs = lhs.getLastChild(); // for(var x in y) {...}
}
if (NodeUtil.isName(lhs)) {
addToDefIfLocal(lhs.getString(), cfgNode, rhs, output);
}
}
return;
case Token.AND:
case Token.OR:
computeMustDef(n.getFirstChild(), cfgNode, output, conditional);
computeMustDef(n.getLastChild(), cfgNode, output, true);
return;
case Token.HOOK:
computeMustDef(n.getFirstChild(), cfgNode, output, conditional);
computeMustDef(n.getFirstChild().getNext(), cfgNode, output, true);
computeMustDef(n.getLastChild(), cfgNode, output, true);
return;
case Token.VAR:
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
if (c.hasChildren()) {
computeMustDef(c.getFirstChild(), cfgNode, output, conditional);
addToDefIfLocal(c.getString(), conditional ? null : cfgNode, c.getFirstChild(), output);
}
}
return;
default:
if (NodeUtil.isAssignmentOp(n)) {
if (NodeUtil.isName(n.getFirstChild())) {
Node name = n.getFirstChild();
computeMustDef(name.getNext(), cfgNode, output, conditional);
addToDefIfLocal(
name.getString(), conditional ? null : cfgNode, n.getLastChild(), output);
return;
} else if (NodeUtil.isGet(n.getFirstChild())) {
// Treat all assignments to arguments as redefining the
// parameters itself.
Node obj = n.getFirstChild().getFirstChild();
if (NodeUtil.isName(obj) && "arguments".equals(obj.getString())) {
// TODO(user): More accuracy can be introduced
// ie: We know exactly what arguments[x] is if x is a constant
// number.
escapeParameters(output);
}
}
}
if (NodeUtil.isName(n) && "arguments".equals(n.getString())) {
escapeParameters(output);
}
// DEC and INC actually defines the variable.
if (n.getType() == Token.DEC || n.getType() == Token.INC) {
Node target = n.getFirstChild();
if (NodeUtil.isName(target)) {
addToDefIfLocal(target.getString(), conditional ? null : cfgNode, null, output);
return;
}
}
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
computeMustDef(c, cfgNode, output, conditional);
}
}
}
private Node tryFoldObjectPropAccess(Node n, Node left, Node right) {
Preconditions.checkArgument(NodeUtil.isGet(n));
if (!left.isObjectLit() || !right.isString()) {
return n;
}
if (NodeUtil.isAssignmentTarget(n)) {
// If GETPROP/GETELEM is used as assignment target the object literal is
// acting as a temporary we can't fold it here:
// "{a:x}.a += 1" is not "x += 1"
return n;
}
// find the last definition in the object literal
Node key = null;
Node value = null;
for (Node c = left.getFirstChild(); c != null; c = c.getNext()) {
if (c.getString().equals(right.getString())) {
switch (c.getType()) {
case SETTER_DEF:
continue;
case GETTER_DEF:
case STRING_KEY:
if (value != null && mayHaveSideEffects(value)) {
// The previously found value had side-effects
return n;
}
key = c;
value = key.getFirstChild();
break;
default:
throw new IllegalStateException();
}
} else if (mayHaveSideEffects(c.getFirstChild())) {
// We don't handle the side-effects here as they might need a temporary
// or need to be reordered.
return n;
}
}
// Didn't find a definition of the name in the object literal, it might
// be coming from the Object prototype
if (value == null) {
return n;
}
if (value.isFunction() && NodeUtil.referencesThis(value)) {
// 'this' may refer to the object we are trying to remove
return n;
}
Node replacement = value.detachFromParent();
if (key.isGetterDef()) {
replacement = IR.call(replacement);
replacement.putBooleanProp(Node.FREE_CALL, true);
}
n.getParent().replaceChild(n, replacement);
reportCodeChange();
return n;
}